RALEIGH — Why use this tool? Most everyone knows that you need something preplant for thrips, whether that is an insecticidal seed treatment or an insecticide in-furrow. But should you use a seed treatment and an in-furrow? What about a foliar spray? This tool can help with those decisions.
What does this tool bring to the table? We have known for some time that thrips injury is a function of weather-driven seedling growth and thrips pressure. This tool uses planting date, temperature, precipitation and knowledge of when thrips pressure will occur and how severe it will be to predict when cotton is at risk.
How can I use this tool? You can use this tool to save time and money on your farm by focusing your most intensive thrips management efforts on cotton that will be planted at a time that is most at risk for thrips. It would also be a good idea to scout these areas more intensively as well (click here for the NC Cotton Scouting Guide). If you base a thrips spray off injury, it is usually too late to prevent damage to the crop. Immature thrips are a good sign that at-plant insecticides are running their course and a spray might be needed. Don’t forget that cotton is most sensitive to thrips damage when the 1st true leaf begins to appear between the cotyledons, as illustrated in the photos. Although foliar sprays at later stages (2-3 true leaves) may occasionally benefit yields, targeting sprays when the 1st true leaf appears has been proven to be the most effective.
When should I use this tool? This tool will give the best predictions within 10-14 days after the date you use it since it is based on weather forecasts. Therefore, you could use this tool two weeks before you plant to make preplant decisions, but you should also check it a few days before you plant. You should also use the tool every week after you plant to track damage potential until cotton is at the four leaf stage.
How do I use this tool? A web-based presentation (click here) has been prepared to guide users on the background of the tool. This presentation includes an overview of how to use this tool for individual locations in North Carolina and the Southeast US Cotton Belt.
How confident should I be with using this tool? Any forecast will have some uncertainty. However, this tool is based on many years of data from across the Southeast US Cotton Belt and has been validated several years since. We are very confident that this tool, when used as instructed, will accurately forecast thrips risk to cotton.
Where can I find the tool? Simply click here to begin using the tool.
Finally, this publication details a summary of several years of thrips research from the Southeast US Cotton Belt regarding 1) tillage and cover crops, 2) starter fertilizer, 3) herbicide and insecticide interactions, 4) insecticide efficacy, and 5) the genesis of the tool to forecast risk for thrips. This publication includes basic information needed to develop an integrated approach to control thrips using several different tactics that reduce thrips damage.
— Dr. Dominic Reisig
Associate Professor and Extension Specialist
Entomology and Plant Pathology – NC State University
For more news from North Carolina, click here.